1. Field of the Invention
The present invention generally relates to frictional drive transmissions that use a plurality of friction transmitting roller pairs. More specifically, the present invention relates to a frictional drive transmission that has a gear shifting mechanism for selectively switching between friction transmitting roller pairs.
2. Background Information
An existing frictional drive transmission employs a structure in which a cam is slid in a direction perpendicular to a pressing force acting against the contacting surfaces of two contacting rollers in order to simplify the assembly of the frictional drive transmission and simplify the adjustment of the applied pressure. More specifically, an elastic member configured and arranged to elongate and contract in the direction perpendicular to the pressing force is provided between the cam and a frame such that the applied pressure can be adjusted with a low-accuracy positioning part (e.g., Japanese Laid-Open Patent Publication No. 2005-256950).
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved frictional drive transmission. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.